1. Field of the Invention
The present invention relates to a method of filling a container that is closable by a lid; the container is filled with a powder. The invention also relates to transfer apparatus associated with said method, which apparatus can be described as a "filler head".
Above, and below in the present text, the apparatus associated with said method of filling is referred to as "transfer apparatus". In any event, said transfer apparatus serves to guide and confine the powder which falls under gravity.
2. Description of Related Art
Said method and apparatus have been developed for the purpose of enabling a powder to be transferred while avoiding any dissemination of said powder outside said apparatus and while avoiding any accumulation of said powder within said apparatus.
Said method and apparatus are particularly suitable for discontinuous transfer of toxic powders, and in particular radioactive powders.
To resolve the technical problem involved, i.e. that of transferring a powder into a container for the purpose of filling the container while avoiding any dissemination of the powder, there exist known apparatuses and in particular apparatuses comprising a tubular body which defines a chamber that can be closed at its bottom end by a valve.
The body is provided with a docking port for receiving the container which is generally closed by a lid. Said port is consequently fitted with means for taking hold of said lid.
A powder-feed duct opens out into the top of the chamber.
After the container has been docked and its lid removed, the valve is opened to put the chamber into communication with the inside of the container.
The powder then flows into the container through the chamber.
To limit the risk of powder being disseminated to the outside, a small degree of suction is maintained in the inside volume of the entire apparatus by means of a ventilation system. The ventilation gas is extracted via a filter column in order to retain the powder entrained thereby.
Such apparatus, although effective, nevertheless leaves zones in which powder accumulates (valve, docking port, . . . ) which can lead to said powder becoming disseminated in operation; and the danger of such dissemination increases with increasing toxicity of said powder.